It was an interesting experience, to say the least. The police knew the place well but no raids (as far as I know) were conducted to round these folks up for deportation. There is a demand for their services. We wouldn't know where to hire help otherwise. This is the kind of jobs that few (if any) Americans are willing to do. Some locals blame them for depressing the wages of American manual laborers. Sounds a lot like the arguments back home in Singapore.
It is a global phenomenon, a product of globalisation.
At the other extreme end of the economic/educational spectrum, there is this. The poster (sakky) has a PhD from MIT.
Prestige, prestige, prestige.